The present invention relates to an agent and kit for use in connection with the diagnosis and therapy of malignant tumors, a method for the production thereof and its use, as well as the use of charged liposomes for the diagnosis and therapy of malignant tumors.
It has been known for quite some time that D- and L-glycerinaldehydes can be effectively used against ascitic tumors in mice [O. Warburg, K. Galveka, A. Gessler and S. Lorenz, Z. Klin. Chem. 1, 175 (1963)]. In accordance therewith, the formation of cancer which is caused by intraperitoneally injected ascites tumor cells in mice can be prevented if, at the same time or on the next day, D- or L-glycerinaldehyde is also administered intraperitoneally. Compounds such as 2-oxopropanol (pyruvaldehyde) [Apple and Greenberg, Cancer Chemotherpaie, 52, 687 (1968); Neoplasma 24, 210 (1970)] as well as acrolein [K. Motycka and L. Lacko, Z. Krebsforschung 66, 491 (1965)] were also effective, although to different extents.
Glycerinaldehyde is a metabolic product and its inhibiting effect on the development of cancer cells has been ascribed to the fact that it apparently impedes the glycolysis [Skamoto, A. and Prasad, K.N.: Cancer Research, 32, 532 (1972)] which is used by cancer cells to a substantial extent as an energy-delivering process. Doses of glycose and insulin accelerate the growth of certain tumors by 8.3 times [Gaison, T. C., Legros, N. and Geimann, R.: Cancer Research 32, 233 (1972)]. It has, however, been found [B. Mendel, Klin. Wschr. 8, 169 (1929)], that only the L-form of glycerinaldehyde is effective as glycolysis inhibitor, for instance, in the case of so-called Jensen's sarcoma while the D-form is not, but, on the other hand, the D-form otherwise has stronger cancerotoxic action than the L-form [O. Warburg, K. Galveka, A. Gessler and S. Lorenz, Z. Klin. Chem. 1, 175 (1963)].
Studies on inhibiting of the incorporation of C labeled nucleosides in DNA and RNA also showed that D-glycerinaldehyde strongly impedes (aerobically and anaerobically) the incorporation of .sup.14 C-thymine into DNA, while L-glycerinaldehyde, although it impedes anaerobically, impedes aerobically only to a slight extent. This shows that there is evidently still some other possibility, aside from the inhibition of glycolysis, for the action of glycerinaldehyde.
Solid tumors are not affected by glycerinaldehyde [N. Brock and P. Neikamp, Z. Krebsforschung 67, 93 (1965)], even if the glycerinaldehyde is administered intravenously, intratumorally or intra-arterially. The authors arrive at the conclusion that glycerinaldehyde cannot be used for the chemotherapy of tumors.
It has also been proposed to increase the concentration of glycerinaldehyde in the animal or human to such an extent that the rapid degradation of the glycerinaldehyde can be counteracted with sufficient assurance and that therefore effects could be expected. Practical tests on this, to be sure, are lacking since such proof could be given only with the use of an artificial kidney [M. v. Ardenne, Naturwiss. 51, 217 (1964)].
U. Ehrenfeld [Krebsgeschehen 5, 132 et seq. (1979)] has reported on the cancerotoxic effect of a mixture of acetaldehyde and ethanol. The mixture contains 3 to 10 g acetaldehyde per 1000 g of ethanol. It was found, however, that the effect of this mixture in the treatment of solid malignant tumors as well as of metastases is insufficient.
Intravenously employed liposomes as carriers of markers and medication are not able to pass through continuous capillary walls; they are, to be sure, taken up rapidly by phagocyting cells [G. Poste, Biol. of the Cell, 47, 19 (1983); F. H. Roerdink, J. Dijkstra, G. Hartman, B. Bolscher and G. Scheephof, Biochem. Biophys. Acta 677, 79 (1981); R. M. Ahra and C. A. Hunt, Biochem. Biophys. Acta 666, 493; C. Nicolau, A. Le Pape, Ph. Soriano, F. Fargette and M.-F. Intrel, Proc. Natl. Acad. Sci. USA 80, 1068 (1983)]. This inability on their part to leave the circulation system has been documented with sufficient certainty [B. E. Ryman, G. M. Barrat, R. H. J. Regent, Biol. of the Cell, 47, 71 (1983); M. Bundgaard, Ann. Rev. Physiol. 42, 325 (1980)], which proved them to be unsuitable for use as direct carriers of markers or medication to or into tumors (V. J. Richardson, B. E. Ryman, R. F. Jewkes, K. Jeyasingh, M. H. N. Tattersal, E. S. Newlands and S. B. Kaye, Br. J. Cancer, 40, 35 (1979)]. A simple administration of liposomes by inhalation failed as a result of the fact that the alveola wall of the lung could not be penetrated by the liposomes within a passage time sufficient for therapy or in case of different administration tissue walls which could correspondingly not be penetrated.
The access path which Poste and Fidler use [G. Poste, R. Kirsch, W. Fogler and I. J. Fidler, Cancer Res. 39, 881 (1979); G. Poste and R. Kirsch, Cancer Res. 39, 2582 (1979); I. J. Fidler, A. Raz, W. E. Fogler, R. Kirsch, P. Bugelski and G. Poste, Cancer Res. 40, 4460 (1980); I. J. Fidler, Z. Barnes, W. E. Fogler, R. Kirsch, P. Bugelski and G. Poste, Cancer Res. 42, 496 (1982)] by intravenously injecting liposomes which contain immune modulators in aqueous phase appears very successful in animals. These liposomes are taken up by monocytes in the blood path which become alveolar macrophages in the lung and as such are activated by the molecules of the immune modulator. They contribute significantly to the control of pulmonary metastases. Because of the above-mentioned inability of the liposomes to leave the circulation without the help of cells, this method, however, could not be employed up to now for diagnosis and therapy in humans.
There is a great need for an agent which is able to improve the passage of liposomes through cellular walls, such as, for instance, the cell walls of the lung, of the blood vessels, of the lymph vesssels, etc., so that the liposomes are able to arrive at the place where they could develop their action when they were charged with medicaments.
The diagnosis of malignant tumors is frequently extremely difficult. Malignant tumors can only be detected by x-ray after they have reached a given size. The formation of small tumors and metastases can frequently not be detected, with the result that malignant tumors frequently can only be incompletely removed upon surgery. Therefore, there is a need for a method of diagnosis by which even small tumors can be detected and recognized in simple and easy manner.
The object of the present invention is therefore to make available an agent and its use in connection with the diagnosis and treatment of malignant tumors, the agent being capable of being produced in simple manner, relatively non-toxic for the patient who is to be treated and not imposing without excessive strain on the body.
It has now surprisingly been found that certain aldehydes of the type described below are able, in higher doses, to effect a direct passage of liposomes through cell walls, particularly the walls of pulmonary alveoli and lymph and blood capillaries. In this way, there is made possible a new method of detecting and a new manner of treating malignant tumors, since the liposomes charged with marker and/or medicament pass directly to the malignant tumor and carry out the greatest possible action there directly for the detection and treatment of the tumor.